Numerous extracorporeal blood oxygenation systems have been devised for purposes of pumping and oxygenating a patient's blood during cardiovascular surgery and/or other situations wherein the normal physiological functioning of the heart and lungs is interrupted or impaired.
Typical blood oxygenation systems of the prior art comprise four major components--(a) a venous reservoir, (b) a heat exchanger, (c) an oxygenator and (d) a blood pump. The "blood pump" portion of the system usually consists of a disposable peristaltic pump mounted directly upon a relatively large permanent motor drive. Some of the prior art blood oxygenation systems, such as that described in U.S. Pat. No. 4,698,207 (Bringham, et al.), have incorporated an integrated assembly comprising the (a) venous reservoir, (b) heat exchanger and (c) oxygenator components of the system. Such integral assembly may be located very close to the body of the patient. However, even when such integral venous reservoir/heat exchanger/oxygenator assembly is employed, it is still necessary to fluidly connect such integral assembly to a remotely positioned pump/control console so that blood may be circulated to the remotely positioned pump/control console wherein the pumping apparatus and system controls are housed.
In most cardiothoracic surgical procedures wherein extracorporeal blood oxygenation is employed, the crowded condition around the operating table generally precludes positioning the large pump/control console at a location immediately adjacent or close to the operating table. Thus, the pump/control console must be positioned some distance away from the table and lengthy blood-filled tubes must be run to and from the console to permit circulation of blood through the pumping apparatus housed in the pump/control console. The relatively long blood-filled tubes running to and from the pump/control console substantially increase the overall volume of the patient's blood which must be maintained in the extracorporeal circuit at any given point in time. Such increase in the length of the blood tubing, and the overall volume of blood in the extracorporeal circuit is undesirable for several reasons. First, it increases the amount of priming fluid (e.g. saline) deployed within the system and subsequently mixed with the patient's blood. Second, such increase in the volume of blood within the extracorporeal circuit will increase the volume of blood and/or blood products which must be administered by transfusion during the operative procedure. Additionally, such increase in the length of the tubing will substantially increase the amount of nonphysiological matter with which the blood comes in contact as it travels through the extracorporeal oxygenation system, thereby heightening the potential for mechanical, chemical and/or immunoloreactive damage to the formed and nonformed elements of the blood.
In view of the foregoing shortcomings of the prior art blood oxygenation systems, there exists a need for a blood oxygenation system which incorporates an integral assembly comprising (a) venous reservoir, (b) oxygenator, (c) heat exchanger and (d) pump, all of which may be positioned directly adjacent or close to the patient so as to eliminate the need for circulation of the patient's blood to a separate pumping device located in the remotely located pump/control console.